Why are trees are green?

Trees are essential to human civilization.

They provide with so many necessary means of survival, including one of the most important ones, which is oxygen.

We have read so much about them since a very young age and we understand their basic functioning.

One crucial element is understanding how in how they function in themselves and provide us with the same.

To do so, we have to ask an important question, which might seem silly but is quite significant.

Green pigmentation is crucial in understanding how trees function and give us the resources that are needed for human civilization.

Importance of plants and trees

Plants are living organisms that need a source of energy to carry out basic biochemical reactions.

This is important as it is a source of carbon to build their bodies.

While animals and humans obtain this energy and carbon from organic compounds like other animals and plants, plants have a different method of doing this. 

These organic compounds are produced only by cyanobacteria and plants in the process of photosynthesis.

Photosynthesis is defined as “synthesis using light”.

Light energy drives the synthesis of glucose from carbon dioxide and water into the generation of oxygen in the plants.

Energy and carbon stored in this glucose can be used by other organisms in trophic chains.

That’s why life on the Earth ultimately depends on plants.

Light spectrum, humans, and colors

Before we jump into understanding the whole process of why trees and plants appear green, we need to analyze some other factors that impact it.

Sunlight is a crucial factor in this.

It's like a rain of photons of different wavelengths.

Our eyes are sensitive only to a small range of wavelength – the so-called visible spectrum.

This variety is very important as the light of different wavelengths appears to us as different colors.

White light appears as white light to us as it is a mixture of light with many different wavelengths.

Short-wavelength light has a high energy content; long-wavelength light has a low energy content
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Now, we need to discuss pigments.

Every leaf on a tree or a plant has a pigment called chlorophyll.

This pigment reflects green light and paints the leaves in green color.

These are located in chloroplasts – special organelles of plant cells.

These chlorophylls are the key pigment molecules driving photosynthesis.

They have evolved in the selection of pigments for absorbing visible light and that part of the Sun’s spectrum with the highest flux. 

To summarise the whole process:

The reason that Green plants are green is that they contain a pigment called chlorophyll.

This Chlorophyll absorbs certain wavelengths of light within the visible light spectrum.

Greenlight is not absorbed but reflected, making the plant appear green. Chlorophyll is found in the chloroplasts of plants.